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Pdf reader improvments (#113)

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* Improve PDF rendering quality and performance.

- Set `FilterQuality.High` when drawing base bitmaps and high-res tiles in `PdfPageComposable`.
- Implement `inSampleSize` calculation in `UniversalDocument` to optimize memory usage during region decoding.
- Enhance bitmap drawing quality by adding `ANTI_ALIAS_FLAG` and `DITHER_FLAG` to the paint configuration.

* Implement custom reader themes for PDF viewer.

This change integrates the `ReaderThemePanel` and theme management logic into the PDF viewer, allowing users to apply preset or custom themes. Previously, the PDF viewer only supported a simple dark mode toggle.

Specific changes:
- Moved `ReaderTheme`, `ReaderTexture`, and theme-related utility functions from `EpubReaderScreen.kt` to `Common.kt` to allow sharing between EPUB and PDF readers.
- Updated `PdfPageComposable` to use `activeTheme` instead of `isDarkMode`, implementing a `ColorMatrix` to apply custom background and text colors to PDF pages.
- Replaced the dark mode toggle in `PdfViewerScreen` with a theme selection button that opens `ReaderThemePanel`.
- Introduced `PdfBuiltInThemes` to provide PDF-specific theme presets.

* Reset page transformation on constraint changes and refine tile rendering logic.

- Reset scale to 1.0 and offset to zero in `PdfPageComposable` when constraints change.
- Update `UniversalDocument` to use floating-point precision for source rectangle calculations and `RectF` for destination mapping to improve rendering accuracy.

* Improve eraser hit detection and visual thickness settings in PDF reader.
This commit is contained in:
Aryan 2026-03-26 13:05:50 +05:30 • committed by GitHub
parent 4db2c97a30
commit 60dacf9c12
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GPG key ID: B5690EEEBB952194
9 changed files with 834 additions and 741 deletions
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97
app/src/main/java/com/aryan/reader/pdf/PdfPageComposable.kt
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@ -407,7 +407,7 @@ internal fun PdfPageComposable(
clearSelectionTrigger: Long = 0L,
onTtsHighlightCenterCalculated: ((Float) -> Unit)? = null,
onSearchHighlightCenterCalculated: ((Float) -> Unit)? = null,
isDarkMode: Boolean = false,
activeTheme: com.aryan.reader.ReaderTheme = com.aryan.reader.ReaderTheme("no_theme", "No Theme", Color.Unspecified, Color.Unspecified, false),
onDoubleTap: ((Offset) -> Unit)? = null,
isEditMode: Boolean = false,
drawingState: PdfDrawingState? = null,
@ -534,41 +534,55 @@ internal fun PdfPageComposable(
val canvasWidthPx = remember { mutableFloatStateOf(0f) }
val canvasHeightPx = remember { mutableFloatStateOf(0f) }
val colorFilter = remember(isDarkMode) {
if (isDarkMode) {
val colorMatrix = floatArrayOf(
-1f,
0f,
0f,
0f,
255f,
0f,
-1f,
0f,
0f,
255f,
0f,
0f,
-1f,
0f,
255f,
0f,
0f,
0f,
1f,
0f
)
ColorFilter.colorMatrix(ColorMatrix(colorMatrix))
} else {
null
val isDarkMode = activeTheme.isDark || activeTheme.id == "reverse"
val colorFilter = remember(activeTheme) {
when (activeTheme.id) {
"no_theme", "system" -> null
"reverse" -> {
val colorMatrix = floatArrayOf(
-1f, 0f, 0f, 0f, 255f,
0f, -1f, 0f, 0f, 255f,
0f, 0f, -1f, 0f, 255f,
0f, 0f, 0f, 1f, 0f
)
ColorFilter.colorMatrix(ColorMatrix(colorMatrix))
}
else -> {
val bgR = activeTheme.backgroundColor.red * 255f
val bgG = activeTheme.backgroundColor.green * 255f
val bgB = activeTheme.backgroundColor.blue * 255f
val fgR = activeTheme.textColor.red * 255f
val fgG = activeTheme.textColor.green * 255f
val fgB = activeTheme.textColor.blue * 255f
val dr = (bgR - fgR) / 255f
val dg = (bgG - fgG) / 255f
val db = (bgB - fgB) / 255f
val lumR = 0.2126f
val lumG = 0.7152f
val lumB = 0.0722f
val colorMatrix = floatArrayOf(
dr * lumR, dr * lumG, dr * lumB, 0f, fgR,
dg * lumR, dg * lumG, dg * lumB, 0f, fgG,
db * lumR, db * lumG, db * lumB, 0f, fgB,
0f, 0f, 0f, 1f, 0f
)
ColorFilter.colorMatrix(ColorMatrix(colorMatrix))
}
}
}
val backgroundColor = remember(isDarkMode, isVerticalScroll) {
if (isDarkMode) {
Color(0xFF2A2A2A)
} else {
val backgroundColor = remember(activeTheme, isVerticalScroll) {
if (activeTheme.id == "no_theme" || activeTheme.id == "system") {
if (isVerticalScroll) Color.White else Color.Black
} else if (activeTheme.id == "reverse") {
if (isVerticalScroll) Color.Black else Color.White
} else {
activeTheme.backgroundColor
}
}
@ -1628,10 +1642,6 @@ internal fun PdfPageComposable(
}
}
if (selectedTool == InkType.ERASER) {
eraserPosition = down.position
}
if (dragStartedOnHandle) {
Timber.d(
"PointerInput: Drag started on handle $activeDraggingHandle"
@ -3091,8 +3101,12 @@ internal fun PdfPageComposable(
}
LaunchedEffect(
this@BoxWithConstraints.maxWidth, this@BoxWithConstraints.maxHeight, pageIndex
this@BoxWithConstraints.maxWidth, this@BoxWithConstraints.maxHeight
) {
scale = 1f
offset = Offset.Zero
onScaleChanged(1f)
Timber.d(
"PdfPageComposable Page $pageIndex | Constraints: maxWidth=${this@BoxWithConstraints.maxWidth}, maxHeight=${this@BoxWithConstraints.maxHeight}"
)
@ -3861,7 +3875,6 @@ private fun PdfBitmapLayer(
.fillMaxSize()
.graphicsLayer()) {
translate(left = centeringOffsetX, top = centeringOffsetY) {
// THIS is the fix: Hard clip to the target bounds so edge tiles can't bleed out.
clipRect(left = 0f, top = 0f, right = targetWidth.toFloat(), bottom = targetHeight.toFloat()) {
if (bitmapState != null && !bitmapState.isRecycled) {
val dstW = if (targetWidth > 0) targetWidth else bitmapState.width
@ -3869,17 +3882,16 @@ private fun PdfBitmapLayer(
val srcSize = IntSize(bitmapState.width, bitmapState.height)
val dstSize = IntSize(dstW, dstH)
// 1. Draw Base Bitmap
drawImage(
image = bitmapState.asImageBitmap(),
srcOffset = IntOffset.Zero,
srcSize = srcSize,
dstOffset = IntOffset.Zero,
dstSize = dstSize,
colorFilter = colorFilter
colorFilter = colorFilter,
filterQuality = androidx.compose.ui.graphics.FilterQuality.High
)
// 2. Draw High-Res Tiles
if (effectiveScale > 1f) {
tiles.forEach { tile ->
if (!tile.bitmap.isRecycled) {
@ -3891,7 +3903,8 @@ private fun PdfBitmapLayer(
dstSize = IntSize(
tile.renderRect.width(), tile.renderRect.height()
),
colorFilter = colorFilter
colorFilter = colorFilter,
filterQuality = androidx.compose.ui.graphics.FilterQuality.High
)
}
}